No matter how good our intentions and efforts, there will be occasions when it is necessary to make a complaint.
One of the most common complaints involve reporting about poor customer service. Naturally, when you have a genuine complaint you will feel upset and tend to use offensive language in your letter. But I strongly urge you to show restraint in your letter, otherwise it would create ill-feeling and cause the other party to be unwilling to help you.
You will gain nothing by being insulting. In fact, you are much more likely to get what you want by being courteous and respectful.
Here’s a sample of a letter of complaint written in a respectful tone and gives clear indication of the reason for dissatisfaction. It also provides all the details for the other party to investigate the matter.